[问答题]
The image shows a food web in a s;6 ) ;uki(j-fvxvoo cialt marsh ecosya.1uiw4f *wx ag;1n pn7s/uwxstem.
1.Identify all the detritivores in the food web shown above.
2.Define secondary productivity.
3.Explain why energy is lost during the transfer from producers to herbivores.
4.Describe a method a farmer could use to estimate the gross primary productivity per month of his wheat crop.
